This invention relates to method and apparatus for connecting a left-handed feed handle to a machine such as a milling machine or a drill press.
Typical milling machines include what is known as a quill in which a tool such as an end mill or a drill, for example, is held and rotatably driven by a drive motor. The quill is vertically movable towards and away from a workpiece table.
Quill-feed speed handles allow an operator to quickly reposition the handle with respect to a quill pinion shaft. Due to the gearing between the pinion shaft and the quill, several rotations of the handle may be needed to move the quill between its extreme positions. However, during actual use, the quill is normally moved vertically only a short distance, e.g., to drill a shallow bore.
Vertical knee-type milling machines include a quill pinion shaft that extends horizontally between right and left sides of a housing of the machine. The pinion can either be rotated manually or rotated by a driven gear for moving the quill towards and away from a workpiece table. Vertical knee-type milling machines are purchased from the manufacturer having apparatus mounted only to the right end portion of the pinion shaft for mounting a handle assembly to the milling machine for providing right hand operation. Heretofore, there has not been any apparatus that would permit a handle assembly to be mounted onto the left end portion of the pinion shaft to facilitate left hand operation. At its left end portion the pinion shaft is supported by the milling machine housing and covered by a clutch arm cover. The clutch arm cover is mounted to the housing by several fasteners that extend through holes in the cover and are threaded to tapped bores in the housing.
Because vertical knee-type milling machines have not been designed with a handle assembly on the left end portion of the pinion shaft, an operator usually only moves the quill manually with his/her right hand on the right-handed handle. This presents problems for milling machine operators who also want to use their left hand on a handle to move the quill manually. Placing his/her left hand on the right-handed handle is undesirable because the operator is put into an awkward position.
In a typical milling machine the right end portion of the pinion shaft carries an overload clutch connected to the pinion shaft upon which a clutch sleeve with a geared portion is disposed. The geared portion of the clutch sleeve can engage a gear driven by a transmission in the milling machine housing. A locknut and a spring are connected to the clutch member for biasing the clutch sleeve away from the locknut in an axial direction of the pinion shaft. A trip lever is connected to a ring on the clutch member for moving the clutch sleeve in the axial direction to engage the clutch sleeve with the driven gear and thereby rotate the pinion shaft to move the quill toward or away from the workpiece. "Speed handles" are now available to replace the rigid fixed handle with which the machine is usually delivered by the manufacturer.
Right-handed speed handle assemblies that are connected to the standard milling machine mounting apparatuses typically include a reciprocally movable pin operatively connected to a handle forming part of the assembly. The handle assembly is maintained to the pinion shaft by a set screw that loosely engages a groove formed in a sleeve member connected to the right end of the pinion shaft. The engagement between the screw and the groove enables the handle to be rotated relative to the pinion shaft while remaining connected to it. The pin under the control of the handle engages a selected one of a plurality of bores formed on an end of the sleeve member, thereby locking the handle to the pinion shaft to prevent relative rotation when the handle member is in the engagement position. An example of a "speed handle" is shown in U.S. Pat. No. 5,267,484 to Cukelj, which is incorporated herein by reference in its entirety. This type of handle enables an operator to disengage the pin from the bores of the sleeve member and rotate the handle relative to the pinion shaft to a desired position where maximum mechanical leverage can be obtained by the operator for the particular machining operation.